The study of tension/compression asymmetry of [111] oriented nickel base single crystal superalloys

The results of experiments show that the macroscopic deformation bands of [111] oriented nickel base single crystal superalloys belong to cubic slip mechanism and microscopic dislocations slip is octahedral. For above results, a zig-zagged cross slip model has been proposed to interpret above phenomenon. This model could characterize both macroscopic cubic deformation and microscopic octahedral slip well. The gradual decrease of the yield strength of nickel base single crystal superalloys with increasing of temperature has been also studied and the model could interpret this phenomenon well. Based on above zig-zagged cross slip model, the tension/compression asymmetry of [111] oriented nickel base single crystal superalloys has been studied and a dissociation mechanism of the superdislocation which could predict the yield strength of tension lower than that of compression has been also proposed. Finally, based on above cross slip model and dissociation mechanism, a yield strength predicted model has been proposed which could characterize tension/compression asymmetry of [111] oriented nickel base single crystal superalloys.